CVE-2026-25765 Faraday affected by SSRF via protocol-relative URL host override in build_exclusive_url
An attacker can exploit a protocol-relative URL handling flaw in the Faraday Ruby library to redirect requests to arbitrary hosts, enabling Server-Side Request Forgery.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-25765?
CVE-2026-25765 is a medium-severity server-side request forgery vulnerability in lostisland faraday, published on 9 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Faraday is an HTTP client library abstraction layer that provides a common interface over many adapters. Prior to 2.14.1, Faraday's build_exclusive_url method (in lib/faraday/connection.rb) uses Ruby's URI#merge to combine the connection's base URL with a user-supplied path. Per RFC 3986, protocol-relative URLs (e.g. //evil.com/path) are treated as network-path references that override the base URL's host/authority component. This means that if any application passes user-controlled input to Faraday's get(), post(), build_url(), or other request methods, an attacker can supply a protocol-relative URL like //attacker.com/endpoint to redirect the request to an arbitrary host, enabling Server-Side Request Forgery (SSRF). This vulnerability is fixed in 2.14.1.
Weakness: CWE-918
Which versions are affected by CVE-2026-25765?
4 open source packages ship an affected version, including faraday. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
faraday RubyGems | From 1.0.0 | 1.10.5 |
faraday RubyGems | From 1.0.0 | 1.10.5 |
faraday RubyGems | From 2.0.0 | 2.14.1 |
faraday RubyGems | From 2.0.0 | 2.14.1 |
Products include Faraday Project Faraday.
How do I fix CVE-2026-25765?
Upgrade faraday to a fixed version for your release line: 1.10.5 or 2.14.1.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-25765 being exploited?
There is no known exploitation of CVE-2026-25765 in the wild and no public exploit code.
Other vulnerabilities in lostisland faraday
Sources
Also known as AZL-77631, AZL-77639, CLEANSTART-2026-FV59211, CLEANSTART-2026-PM67470, DEBIAN-CVE-2026-25765, GHSA-33mh-2634-fwr2 and 23 more.